Aerial platform hydraulic control mechanism having override linkage



E- STILWELL AERIAL PLATFORM HYDRAULIC CONTROL MECHANISM Dec. 26, 1967 HAVING OVERRIDE LINKAGE 2 Sheets-Sheet 1 Filed June 13, 1966 INVENTOR Jack E. Sfi/we/l United States Patent M 3,360,076 AERIAL PLATFORM HYDRAULIC CONTROL MECHANISM HAVING OVERRIDE LINKAGE Jack E. Stilwell, Overland Park, Kaus., assignor to Pitman Manufacturing Company, Grandview, M0., a corporation of Missouri Filed June 13, 1966, Ser. No. 556,979 Claims. (Cl. 182-148) This invention relates to aerial devices having a boom and hydraulically actuated mechanism therefor and, more particularly, to the manual controls for operating the mechanism to manipulate the boom.

Hydraulically operated aerial devices have particular utility when it is desired to elevate a workman to a position where it is possible for him to service an electrical transmission line, prune a tree, or perform other activities on objects which are unaccessible from the ground. When such a device is used for work of this type, a personnel carrier is attached to the outermost end of the boom assembly, and generally, a set of control components are mounted adjacent the personnel carrier on the end of the boom so that a workman in the carrier may manipulate the device to position himself in the most advantageous location to perform the required activities.

Additionally, for practical reasons, as well as to provide a measure of safety to the over-all operation, a secondary control assembly is generally provided adjacent the base of the boom so that a workman on the ground may manipulate the boom and thereby change the position of the personnel carrier. Hydraulically actuated devices of this type are provided with shiftable valve means for directing the flow of hydraulic fluid. The valve means may be shifted one way to operate the mechanism for moving the boom in a first direction and shifted the opposite way to operate the mechanism for moving the boom in the reverse direction. When the valve means is located in the normal central location thereof, the boom is maintained in a preset position. Because the valve must be shifted positively in two different directions so that the internal porting may be positioned to perform the operation as described in the foregoing, the remote carrier control components and the secondary control assembly at the base of the boom must be mechanically linked.

In view of the nature of the activities often performed by a workman in the personnel carrier, and particularly when the workman is Working on energized electrical lines, it is possible that such a workman might become incapacitated by electrical shock or otherwise. Should this occur, there is a possibility that this body might fall across the adjacent carrier control components, rendering them inoperable. It is necessary that such an incapacitated workman be quickly extracted from his precarious position and there is a need for having such secondary controls which operate independently of the remote carrier control components.

It is, therefore, the primary object of the instant invention to provide a secondary control and override assembly for manipulating the hydraulically actuated operating mechanism of an aerial device from the base of the boom independently of the control components disposed adjacent the elevated personnel carrier, so that the boom of such a device may be readily operated from the ground level not only in the event that a workman in the personnel carrier becomes incapacitated and the control components jammed, but also for normal use of the equipment either when a workman is not in the carrier or in those cases where a worker on the ground desires to control movement of the carrier.

As a corollary to the foregoing object, it is an important aim of the instant invention to provide shiftable con- 3,360,076 Patented Dec. 26, 1967 trol structure for shifting the hydraulic valve to manipulate the boom wherein the elevated control components are operable to shift the structure through a clutch which can be readily uncoupled, to the end that the structure may be operated independently of the control components.

An important object of the instant invention is to provide such a clutch having a pair of normally interengaged parts wherein one of the parts is coupled with the shiftable control structure so that a single handle may be first shifted in one. direction to disengage the parts and then manipulated in a different direction to operate the aerial device.

In the drawings:

FIGURE l is a perspective view of an aerial device embodying the principles of the instant invention;

FIG. 2 is an enlarged, fragmentary, top plan vlew, partially in section, of the secondary control assembly for operating the aerial device shown in FIG. 1 from the gro nd;

' FIG. 3 is a fragmentary, cross-sectional, side elevational view taken along line 3-3. of FIG. 2;

FIG. 4 is an enlarged partially cross-sectional, front elevational view of the secondary control assembly taken along line 44 of FIG. 3;

FIG. 5 is a fragmentary, side elevational View taken along line 55 of FIG. 4; and

FIG. 6 is an enlarged, fragmentary, side elevational view of the secondary control assembly as shown in FIG. 3. With the clutch parts disengaged.

A hydraulically operated aerial device embodying the principles of the instant invention is broadly designated by the numeral 10. Device 10 is normally mounted on a truck (not shown) or other suitable means for transporting the device from place to place. Device 10 has a turntable 12 rotatably mounted on a pedestal 14 for swinging in a horizontal plane, pedestal 14 being rigidly aifixed to the transporting means.

A boom assembly 16 is mounted on turntable 12 by hinge means 18 and swingable thereon in a vertical plane. Boom assembly 16 includes an outer housing 20 and a stinger 22 telescoped within housing 20 and extendable and retractable with respect thereto. An aerial platform in the nature of a personnel carrier 24 is swingably attached to the outer end of stinger 22 by mounting means 26. Hydraulically actuated operating mechanism in the nature of a hydraulic cylinder 28 is included in device 10 for swinging boom assembly 16 in a vertical plane relative to turntable 12. Device 10 also includes hydraulically actuated operated mechanism (not shown) in the nature of a double-acting hydraulic cylinder for extending and retracting stinger 22 relative to housing 20, and a hydraulically driven turbine motor for rotating turntable 12 in a horizontal plane relative to pedestal 14.

It is to be understood that the principles of the instant invention have been incorporated into device 10 for purposes of illustration only, and it will be apparent to those skilled in the art that these principles may be utilized in the design of other similar devices such as, for example, one having a collapsible boom.

Device 10, as explained above, includes mechanism for manipulating the boom and the personnel carrier along three different .axes. Shiftable valvemeans 30 in the nature of independently shiftable valve members 32a, 32b and 32c are operably associated with the mechanism for selectively and respectively controlling the manipulation of the boom along each axis. For example, valve member 32a may be coupled with the hydraulic cylinder 28 for swinging boom 16. around hinge 18 relative to turntable 12; valve 32b may be associated with the hydraulic turbine motor (not shown) for rotating turntable 12 relative to pedestal 14; and valve member 32c may be associated with the hydraulic cylinder (not shown) for extending and retracting stinger 22 relative to housing 20.

Carrier control components 38 in the nature of lever arms 40 are provided on the outermost end of stinger 22 adjacent carrier 24 for manipulation of the hydraulic mechanism by a workman therein. Movable valve control linkage 42 presenting individual linkage means 44 is coupled with the arms 40 for operation of the valve means 30 thereby through a secondary control and override as sembly 46.

Each linkage means 44 includes a telescopic shaft 48 rotatably mounted in the boom 16. Each shaft 48 has an outer section 50 which is extendable and retractable with stinger 22, rigid with a respective arm 40, and rotatable as the latter is actuated. Each section 50 has a longitudinally extending inner bore 52 which is transversely square in cross section for receiving an elongated rod 54 with a cross-sectional configuration corresponding to the bores 52. Rods 54 are stationary with relationship to outer housing 20 and, as stinger 22 and sections 50 are extended and retracted, the rods 54 slide relatively into and out of bores 52. Thus, as a section 50 is rotated in response to an actuation of a corresponding arm 40, a respective rod 54 will likewise be rotated. A crank tab 56 extends laterally away from each rod 54, and a reciprocable push bar 58 is connected to each tab 56 by hinge means 60 whereby a rotational movement of a respective rod 54 is translated into a reciprocation of a cor-responding bar 58.

The secondary control and override assembly 46 is located at the base of boom 16 remote from carrier 24 and comprises shiftable control structure 62 presenting operating levers 64, clutch means 66 including separate clutch apparatuses 68, and a fulcrum bar 70. Each of the levers 64 has one end 72 thereof joined to a respective valve member 32 by pivot structure 74, while the other end thereof presents a handle '76 for access by a workman on the ground. Levers 64 are disposed substantially parallel to one another in spaced-apart relationship and each has a slot 78 therein intermediate the ends thereof. Each slot 78 is elongated and extends longitudinally of a respective lever, the slots being in substantial alignment with one another in a direction perpendicular to the longitudinal axes of the levers 64, and the bar is received within slots 78.

Each clutch apparatus 68 includes a shiftable link in the nature of a bell crank 80 having a pair of arms 82 and 84 and a hub 85. Each crank 80 has a bearing opening '86 therein and is rotatably mounted on bar 70 adjacent a respective lever 64 with bar 70 received through openings 86 and with the hub disposed coaxially with bar 70. Arm 84 of each crank 80 has an aperture 88 therein and the arms 82 are pivotally connected to a respective reciprocable bar 58 by pivot means 90 for rotation of a respective crank 80 about fulcrum bar 70 by the corresponding push bar 58 as the latter is reciprocated.

The pivot structures 74 are operable to permit the levers 64 to be shifted longitudinally of bar 70 and of hubs 85 to assume the position shown in dashed lines in FIG. 2. The slots 7 8 are sufficiently elongated to allow such shi fting without binding on a respective hub 85. Structures 74 are also operable to permit vertical pivoting of the ends 72 of the levers 64 relative to the valve members 32 to facilitate shifting of the latter as the levers 64 are rotated about bar 70 on the fulcrums provided by the cooperation of the Walls of slots 78 with the hubs 85 of hell cranks 80.

Each apparatus 68 also includes a pin 92 rigid with a respective lever 64 and extending therefrom toward aperture 88 in the corresponding and adjacent bell crank 80, and means biasing each lever 64 toward the corresponding bell crank 89 in the nature of a helical compression spring 4 mounted coaxially with bar 70. Each spring 94 thereby biases a respective pin 92 into a corresponding aperture 88 to present a pair of normally interengaged parts 96.

Operation In the normal operation of device 10, valve members 32a, 32b, 320 may each be manipulated individually with either the respective lever 64 or the respective arm 40 therefor. As an arm 40 is pushed relatively away from the carrier 24, the corresponding rod 54 is rotated clockwise to assume the dashed line position thereof as seen in FIG. 3. Thus, bar 58 is pulled to the right and bell crank 80 is rotated in a clockwise direction around bar 76. The interaction between pin 92 and aperture 88 causes a corresponding clockwise rotation of lever 64 about bar 70. Therefore, end 72 of lever 64 is shifted downwardly and the valve member 32 is likewise shifted downwardly.

In the same manner, as an arm 40 is pulled relatively toward the carrier 24, the corresponding valve member 32 will be shifted upwardly.

Valve members 32a, 32b and 32c may be shifted individually by shifting the handle 76 of a corresponding lever 64 either upwardly or downwardly, even with pin 92 and aperture 38 interengaged, so long as arms 40 are free to move. However, if arms 40 .are not free to move, each lever 64 may first be shifted longitudinally of the respective hub 85, against the bias of a respective spring 94, sufiiciently to withdraw the corresponding pin 92 from aperture 88 therefor, and into the position shown in broken lines in FIG. 2. In this position, handle 76 of lever 64 is free to be shifted by an operator on the ground either upwardly or downwardly to shift a corresponding valve member 32a, 321) or 32c, respectively. downwardly or upwardly. Viewing FIG. 6, the disposition of pin 92 with respect to aperture 88 is shown after disengagement has occurred and after lever 64 has been shifted relative to crank 80 to shift valve member 32. When lever 64 has been shifted to disengage pin 92 from aperture 88, the arm 40 is free to move without trans- 'milting motion to valve members 32. To engage pin 92 with aperture 88, it is necessary only to release lever 64 and then move arm 40 to the neutral position at which point pin 92 Will be forced into aperture 88 by the action of spring 94.

Thus, when the principles of the instant invention are utilized in the design of a device such as device 10, a control system is provided which permits selective actuation of the hydraulic operating mechanism of the device from either :a position adjacent the personnel carrier or a position adjacent the base of the boom and, further provides an override so that the device may be operated from the base of the boom even when the remote control components located at the outwardmost extremity of the boom are jammed.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. For use with the hydraulically actuated operating of an aerial device having a boom, a personnel carrier on the boom, shiftable valve means operably associated with the mechanism for selective control thereof, carrier control components for the mechanism and mounted for access by a workman in the carrier, and movable valve control linkage extending along the boom and coupled to said control components for movement thereof, the combination with said valve means of a secondary control and override assembly comprising:

shiftable control structure remote from said carrier and operably coupled to said valve means for shifting the latter in response to manual operation of the structure; and

clutch means operably joining the movable linkage to said structure for operating the valve means through the structure upon actuation of the components, said clutch means including normally interengaged parts joined to the structure and said linkage respectively, said structure being mounted for selective movement in a direction different from the direction of travel thereof for shifting the valve means, to effect uncoupling of the parts whereby the structure may thereafter be manually manipulated to shift the valve means independently of the movable linkage and the control components.

2. The invention of claim 1, wherein said clutch means includes,

' a shiftable link having an aperture therein and operably coupled with said linkage for movement thereby when said control components are actuated,

a pin rigid with said structure, extending therefrom in a direction opposite to the direction of selective movement thereof and positioned to normally be received in said aperture in the link whereby, upon movement of the link, the structure is moved therewith through the connection provided by said pin, and

means normally biasing the structure toward a position with said pin received in the aperture therefor.

3. The invention of claim 2, wherein is included,

a fulcrum bar spaced from said valve means, and

said structure includes an elongated operating lever, one

end thereof being coupled with said valve means, the other end of said lever presenting a handle for access by a workman n the ground,

said lever having an elongated slot therein receiving said bar, said slot being disposed intermediate said ends and extending longitudinally of said lever to permit shifting of the lever in a direction longitudinally thereof relative to the bar when the lever is shifted in a direction to displace the pin from the aperture therefor in said link.

4. The invention of claim 1, wherein said valve means includes a plurality of independently shiftable valve members, said structure includes an elongated operating lever joined to each of said valve members for shifting the latter, said control linkage includes an individual linkage means for each of said valve members, and said clutch means includes a separate clutch apparatus for independently coupling each respective linkage means to a corresponding operating lever, whereby each of the operating levers may be swung as required to shift the valve memher connected thereto relative to the remaining valve members and independently of the control linkage means.

5. The invention of claim 4, wherein is included a fulcrum bar spaced from said valve members and pivot structure for joining One end of each of said levers to a respective valve member, the other end of each lever presenting a handle for access by a workman on the ground,

said levers being disposed substantially parallel to one another and in spaced-apart relationship, each lever having a slot therein intermediate the ends thereof, said slots being in substantial alignment with one another in a direction perpendicular to said levers, said bar being received in said slots, each of said slots being elongated and disposed to extend longitudinally of a respective lever to permit swinging of the latter on said valve member in a direction longitudinally of said bar, and wherein each of said clutch apparatuses includes a bell crank having a pair of arms and rotatably mounted on said bar adjacent a respective lever, a pin rigid with a respective lever and extending therefrom toward said crank, and a spring for biasing the lever toward the crank, one of the arms of each crank having an aperture therein, the other of the arms of each crank being coupled with a respective linkage means for rotation thereby about said bar when a respective control component is actuated, each of said pins being positioned to normally be received in a corresponding aperture when the lever is shifted toward the respective crank under the influence of the respective spring, whereby upon rotation of the crank about the bar, the lever is normally rotated therewith about the bar through the connection provided by said pin and whereby said pin is withdrawn from said aperture upon selective swinging of said lever longitudinally of said bar against the bias of said spring.

References Cited UNITED STATES PATENTS 3,066,756 12/1962 Broderson et al. 182-2 3,127,952 4/1964 Baerg t 182-2 3,146,853 9/1964 Eckels 182-2 REINALDO P. MACHADO, Primary Examiner. 

1. FOR USE WITH THE HYDRAULICALLY ACTUATED OPERATING OF AN AERIAL DEVICE HAVING A BOOM, A PERSONNEL CARRIER ON THE BOOM, SHIFTABLE VALVE MEANS OPERABLY ASSOCIATED WITH THE MECHANISM FOR SELECTIVE CONTROL THEREOF, CARRIER CONTROL COMPONENTS FOR THE MECHANISM AND MOUNTED FOR ACCESS BY A WORKMAN IN THE CARRIER, AND MOVABLE VALVE CONTROL LINKAGE EXTENDING ALONG THE BOOM AND COUPLED TO SAID CONTROL COMPONENTS FOR MOVEMENT THEREOF, THE COMBINATION WITH SAID VALVE MEANS OF A SECONDARY CONTROL AND OVERRIDE ASSEMBLY COMPRISING: SHIFTABLE CONTROL STRUCTURE REMOTE FROM SAID CARRIER AND OPERABLY COUPLED TO SAID VALVE MEANS FOR SHIFTING THE LATTER IN RESPONSE TO MANUAL OPERATION OF THE STRUCTURE; AND CLUTCH MEANS OPERABLY JOINING THE MOVABLE LINKAGE TO SAID STRUCTURE FOR OPERATING THE VALVE MEANS THROUGH THE STRUCTURE UPON ACTUATION OF THE COMPONENTS, SAID CLUTCH MEANS INCLUDING NORMALLY INTERENGAGED PARTS JOINED TO THE STRUCTURE AND SAID LINKAGE RESPECTIVELY, SAID STRUCTURE BEING MOUNTED FOR SELECTIVE MOVEMENT IN A DIRECTION DIFFERENT FROM THE DIRECTION OF TRAVEL THEREOF FOR SHIFTING THE VALVE MEANS, TO EFFECT UNCOUPLING OF THE PARTS WHEREBY THE STRUCTURE MAY THEREAFTER BY MANUALLY MANIPULATED TO SHIFT THE VALVE MEANS INDEPENDENTLY OF THE MOVABLE LINKAGE AND THE CONTROL COMPONENTS. 